I have a method for busting skill walls, and I've used it to improve my 4k really quickly this week. If you are already a flashlight player, this post is probably irrelevant. But if you haven't really played around with Flashlight yet, try it out, maybe it'll work for you too:
Use flashlight mod and play songs that are comfortable but still dense for you. Lower the scroll speed, it will probably be pretty hard at first.
Don't worry about accuracy, just try to get a good feel for the notes and rhythms. Keep your hands relaxed and comfortable, resting on the keys or lightly bouncing. If you really want to, you can adjust you judgement line so the lower scroll speed feels more comfortable. Once you feel more comfortable with Flashlight, crank up the map difficulty until you start to fail songs. This is okay.
Now, turn off Flashlight and go play some maps you can barely pass with 500k-600k score at your usual scroll speed. Try to read the notes in large horizontal sections like you did in Flashlight mode and have a fun time playing maps you couldn't pass before. Keep going until your hands start to feel a little bit tired, then slowly decrease the map difficulty as you run a rampage through maps that you thought were hard.
Then take a break.
**I play with scroll speed 22/23 so maybe the slow scroll speed flashlight reading won't be as beneficial for you.
